Device for overcoming dead-centers



(N0 IVIodel.)V

S. 'I'. SHORTESS.

DEVICE FOR OVEROOMING DEAD CENTERS. No. 356,558; Patented Jan. 25, 1887.

N, PETERS, Phommnamphu, wmmngw". D. c.

v sition of the pitman by a cross-section.

Arena* Ormea STEPHEN SHORTESS, OF VINTON, IOWA.

DEVICE FOR OVERCOMING DEADHCENTERS.A

SPECIFICATION forming part of LettersPatent No. 356,558, dated January 25, 1887.

Application [led .Tune 24,1886. Serial No. 206,152. (No model.)

To @ZZ whom, t may concern:

Beit known that I, STEPHEN T. Srronrnss, a citizen of the United States, residing at Vinton, in the county of Benton and State of Iowa, have invented certain new and useful Improvements in Devices for Overcoming Dead- Oenters; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters and iigures of reference marked thereon, which form a part of this specification.

This invention relates to improved means for overcoming dead-centers; and it consists in the novel features more fully hereinafter set forth,cla imed, and shown in the annexed drawings, in whichh l Figure lis a side view of a treadle movement provided with my device. Fig. 2 is a similar view showing the position ofthe parts changed,and showing a modified form in dotted lines. Fig. 3 is an enlarged detail plan view of the improvement, showing the relative po- Fig.

' 4 is a modified form, shown in side elevation.

Fig. 5 is another modification. another modification.l

llhe frame A, crank B, pitnlan C, and treadle D are of well-known construction, and are simply shown as a means to illustrate the application of my improvement, which consists, essentially, of a yieldingly-connected reversible bar, so' disposed that the crank is normally held off a dead-center, and in practice is carried past such points.

The soul of my invention is the combination, with a crank or pitman, of a reversible bar, and a yielding connection interposed between it and said crank or pitman to normally hold the crank offa dead-center. For convenience of reference, the yielding connection in the following description will be designated and referred to as the spring F. It will be noticed that there may be one or more of suchsprings, as desired, and when two are madeuseof one is loca-ted on each side of the pitman, for the purpose presently to be made known.

The reversible bar E is pivotally supported, and springs F, extending in opposite directions Fig. o is sun from arms e, have the inner ends connected with the pitman, or they may be directly connected with the crank, as shown by dotted lines in Fig. 4. The bar and springs are so disposed that the pitman is normally held off a dead-center. The bar is at an angle to a line passing through its pivotal support, so that by changing the position 0fthe bar and elevating the end previously lowered the position of the crank will be changed so that it may berun in an opposite direction. If the bar is changed so as to cross the line of pitman at right angles,

the crank is released from the control of the' springs. This may be easilyunderstood by reference to the figures of the drawings, in which the bar is shown oppositely arranged, or

in different relative positions, and the parts,

correspondingly changed. The upper spring draws the crank toward itself past the lower point of the dead-center, and the lower spring draws the crank toward itself at the upper point of the dead-center. One spring may be used by so adjusting it that it will push at one and pull at the other point of dead-center; but two are preferable, as by their use the degree of tension can be regulated and a smoother and more reliable motion secured. Any suitable fastening device may be made use of to hold the bar in either position; but that shown is preferred, owing to its simplicity and the facility with which it may be operated. It consists of a spring-latch, Gr, secured to that side of the bar adjacent to the frame of the machine, adapted to engage the notches g in the frame.

The tension of the springs may be varied, as occasion may require, by nuts f, located on each side of the arms on threaded extensions of the springs passing through said arms, or by moving the arms bodily to and from each other, or by both-said adjustments. Instead of passing the end of the spring through the arm, it is preferable in some cases to use a bolt, the bolt being threaded and provided with nuts for regulating the tension, and having an eye in one end to which a link is fastened,.the spring being fastened to the link.

The reversible bar may be provided with a handle to be grasped while changing the position, as shownh in Fig. 4. rllhe bar may be pivoted to the pitman and held in position by the spring-latch, and the springs attached to a frame at the side of the pitman with the same result, as shown by dotted lines inFig. 2.

In another modification the bar is pivoted to the pitman near its lower end, so that the arms extend upward on either side of the pitman. The springs are then fastened to arm and ptman,as already described. Th ere should be slots running lengthwise of the bar, at each end of it, for pivoting to the frame. In use one end of the bar is fastened to the frame by bolt ing through the slot, so that the bar will play freely on the bolt. The slot is to prevent binding from the reverse motion of the bar and treadle. Changing the pivotal support to the other end of the bar reverses motion of the crank, which may be done in the manner indieated by full lines, Fig.

This invention has a decided advantage over other devices, in that by the use of a spring on each side of the pitman or crank, each spring controlling its own point of dcad-cen ter, and reversible bar, it is far easier to reverse motion, and it also provides for regulating the degree of tension of the springs, as each can be regulated independently and only given sulicient tension to carry the crank past its point of dead-center.

Fig. 6 shows the reversible bar yieldingly connected with the pitman C bythe spring F and the rodf.

In the use of this device, Where it is not dcsirable to reverse motion, the reversible bar may be dispensed with and the springs fastened to any convenient points in the proper direction to give the desired motion. Instead of the coil-springs shown, the arms may be 2. The combination, With the crank or pitman, ofthe pivotallysupported reversible bar yieldingly connected with the crank or pitman.

3. The combination, with the crank or pitman, of the reversible bar having arms projecting therefrom, which arms are yieldingly connected with the crank or pitman, substantially as and for the purpose set forth.

4. The combination, with the crank or pitman, of the reversible bar, the arms adjustably connected with the bar, and the springs connecting the arms and the crank or pitman, substantially as described.

5. The combinatiom'with the crank or pitman, of an independent spring located on each side oi' the crank or pitman, each exerting a force to carry the crank past its dead-points, and means, substantially as described, for regulating the tension of each spring, substan tially as set forth.

In testimony whereof I affix my signature, in presence of two Witnesses.

STEPHEN T. SHORTESS.

"Witnesses:

W. P. VHIPPLE, JOHN GHRIsTIE. 

